Abstract Body

Background: Recurrent respiratory tract infections (RRTIs) frequently affects children. It is widely accepted that RRTIs in childhood represents a problem per se in addition to an increased predisposition to future respiratory problems. In this regard, bacterial lysates were introduced in human therapy many decades ago.

Purpose: To identify the efficacy of bacterial lysates in the secondary prevention of recurrent RTIs in children.

Methods: Published randomized controlled trials (RCTs), meta-analysis, systematic reviews, and clinical oriented guidelines were searched using multiple bibliographic databases in the last 20 years. The mesh words used were: recurrent respiratory tract infections, bacterial lysates, OM-85, sublingual vaccine, oral immunotherapy. The level of evidence and strength of recommendation was graded according to SORT of the American Academy of Family Physicians.

Results: 103 studies were found, but only 6 were retained as relevant trials (3 RCTs, 2 meta-analyses, and 1 systematic review). The RCTs and the meta-analysis reported a decrease in the number of RRTIs. The systematic review showed that the evidence in favor of bacterial lysates in the prevention of RRTIs in children was weak. There is a trend for fewer and shorter infections as well as a smaller reduction of antibiotic use.

Conclusion: The strength of recommendation in favor of using bacterial lysates to prevent RRTIs is B. Further confirmatory evidence from high-quality and large-scale RCT trials is required.